Day3 教学示例：增强版计算器接入 + QMainWindow/QSS 两版参考实现

- calculator_designer_ext（Day2 增强版：表达式求值 + 括号，递归下降解析器）接入 cmake - calculator_mainwindow（Day3 上午）：增强版计算器装进 QMainWindow，菜单/状态栏/历史停靠窗，纯代码 + 显式 connect，与 mainwindow_showcase 形成坑卡对照 - calculator_mainwindow_qss（Day3 下午）：上午版 + QSS 双主题美化（按键分色/伪状态/深浅切换） - 验证 mainwindow_showcase（QMainWindow 六大组件综合演示，.ui + .qrc） - OUTLINE_4DAY.md / ASSIGNMENTS.md Day3 衔接增强版起点 + 参考实现指引 - 补提交 Day2 calculator/ 与 calculator_designer/ 参考实现（CMakeLists 已引用） - 全量构建 28/28，4 目标离屏自测退出码 0 Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-07-07 22:59:05 +08:00
parent ea6f12e7ac
commit 05a685c952
45 changed files with 4599 additions and 6 deletions
@@ -0,0 +1,229 @@
+#include "calculatordesigner.h"
+
+#include <QPushButton>
+
+#include "expressionevaluator.h"
+#include "ui_widget.h"
+
+namespace {
+bool isOperatorChar(QChar ch) {
+    return ch == QLatin1Char('+') || ch == QLatin1Char('-') ||
+           ch == QLatin1Char('*') || ch == QLatin1Char('/');
+}
+
+bool isDigitOrDotChar(QChar ch) {
+    return ch.isDigit() || ch == QLatin1Char('.');
+}
+}  // namespace
+
+CalculatorDesigner::CalculatorDesigner(QWidget* parent)
+    : QWidget(parent), ui(new Ui::CalculatorForm) {
+    ui->setupUi(this);   // 表单里的控件树 + QGridLayout 全部由 Designer XML 建好
+
+    connect(ui->btn0, &QPushButton::clicked, this, [this] { onDigit(0); });
+    connect(ui->btn1, &QPushButton::clicked, this, [this] { onDigit(1); });
+    connect(ui->btn2, &QPushButton::clicked, this, [this] { onDigit(2); });
+    connect(ui->btn3, &QPushButton::clicked, this, [this] { onDigit(3); });
+    connect(ui->btn4, &QPushButton::clicked, this, [this] { onDigit(4); });
+    connect(ui->btn5, &QPushButton::clicked, this, [this] { onDigit(5); });
+    connect(ui->btn6, &QPushButton::clicked, this, [this] { onDigit(6); });
+    connect(ui->btn7, &QPushButton::clicked, this, [this] { onDigit(7); });
+    connect(ui->btn8, &QPushButton::clicked, this, [this] { onDigit(8); });
+    connect(ui->btn9, &QPushButton::clicked, this, [this] { onDigit(9); });
+    connect(ui->btnDot, &QPushButton::clicked, this, [this] { onDot(); });
+
+    connect(ui->btnPlus, &QPushButton::clicked, this, [this] { onOperator(QLatin1Char('+')); });
+    connect(ui->btnMinus, &QPushButton::clicked, this, [this] { onOperator(QLatin1Char('-')); });
+    connect(ui->btnMul, &QPushButton::clicked, this, [this] { onOperator(QLatin1Char('*')); });
+    connect(ui->btnDiv, &QPushButton::clicked, this, [this] { onOperator(QLatin1Char('/')); });
+
+    connect(ui->btnLeftParen, &QPushButton::clicked, this, &CalculatorDesigner::onLeftParen);
+    connect(ui->btnRightParen, &QPushButton::clicked, this, &CalculatorDesigner::onRightParen);
+
+    connect(ui->btnEquals, &QPushButton::clicked, this, &CalculatorDesigner::onEquals);
+    connect(ui->btnClear, &QPushButton::clicked, this, &CalculatorDesigner::onClear);
+    connect(ui->btnBackspace, &QPushButton::clicked, this, &CalculatorDesigner::onBackspace);
+
+    onClear();
+}
+
+CalculatorDesigner::~CalculatorDesigner() { delete ui; }
+
+void CalculatorDesigner::onDigit(int digit) {
+    if (m_error) onClear();
+    if (m_resultShown) {
+        m_expression.clear();
+        m_openParenCount = 0;
+        m_resultShown = false;
+    }
+
+    const QString token = currentOperandToken();
+    if (token == QStringLiteral("0")) {
+        m_expression.chop(1);  // 用新数字替换孤立的前导 0，避免出现 "007"
+    } else if (currentOperandDigitCount() >= kMaxOperandLength) {
+        return;  // 达到单个运算数的长度上限，忽略后续数字
+    }
+    if (m_expression.size() >= kMaxExpressionLength) return;
+
+    m_expression.append(QString::number(digit));
+    refreshDisplays();
+}
+
+void CalculatorDesigner::onDot() {
+    if (m_error) onClear();
+    if (m_resultShown) {
+        m_expression.clear();
+        m_openParenCount = 0;
+        m_resultShown = false;
+    }
+
+    const QString token = currentOperandToken();
+    if (token.contains(QLatin1Char('.'))) return;  // 当前运算数已有小数点
+
+    const int appended = token.isEmpty() ? 2 : 1;  // 空token时需要补一个前导 0
+    if (m_expression.size() + appended > kMaxExpressionLength) return;
+
+    if (token.isEmpty()) m_expression.append(QLatin1Char('0'));
+    m_expression.append(QLatin1Char('.'));
+    refreshDisplays();
+}
+
+void CalculatorDesigner::onOperator(QChar op) {
+    if (m_error) return;
+    if (m_resultShown) {
+        m_expression = m_lastResultText;
+        m_resultShown = false;
+    }
+
+    if (m_expression.isEmpty()) {
+        if (op != QLatin1Char('-')) return;  // 表达式开头只允许负号（单目负号）
+    } else {
+        const QChar last = m_expression.at(m_expression.size() - 1);
+        if (last == QLatin1Char('(')) {
+            if (op != QLatin1Char('-')) return;  // 左括号后只允许负号
+        } else if (isOperatorChar(last)) {
+            m_expression.chop(1);  // 连续按运算符时，用新的运算符替换上一个
+        }
+    }
+
+    if (m_expression.size() >= kMaxExpressionLength) return;
+    m_expression.append(op);
+    refreshDisplays();
+}
+
+void CalculatorDesigner::onLeftParen() {
+    if (m_error) onClear();
+    if (m_resultShown) {
+        m_expression.clear();
+        m_openParenCount = 0;
+        m_resultShown = false;
+    }
+
+    if (!m_expression.isEmpty()) {
+        const QChar last = m_expression.at(m_expression.size() - 1);
+        if (!isOperatorChar(last) && last != QLatin1Char('(')) {
+            return;  // 数字或右括号后不支持隐式乘法，忽略
+        }
+    }
+    if (m_expression.size() >= kMaxExpressionLength) return;
+
+    m_expression.append(QLatin1Char('('));
+    ++m_openParenCount;
+    refreshDisplays();
+}
+
+void CalculatorDesigner::onRightParen() {
+    if (m_error) return;
+    if (m_resultShown) return;
+    if (m_openParenCount <= 0 || m_expression.isEmpty()) return;
+
+    const QChar last = m_expression.at(m_expression.size() - 1);
+    if (isOperatorChar(last) || last == QLatin1Char('(')) return;  // 括号内需要完整子表达式
+    if (m_expression.size() >= kMaxExpressionLength) return;
+
+    m_expression.append(QLatin1Char(')'));
+    --m_openParenCount;
+    refreshDisplays();
+}
+
+void CalculatorDesigner::onEquals() {
+    if (m_error) return;
+    if (m_expression.isEmpty()) return;
+
+    QString toEvaluate = m_expression;
+    for (int i = 0; i < m_openParenCount; ++i) toEvaluate.append(QLatin1Char(')'));  // 自动补全未闭合括号
+
+    const ExpressionEvaluator::Result result = ExpressionEvaluator::evaluate(toEvaluate);
+    if (!result.ok) {
+        showError();
+        return;
+    }
+
+    const QString resultText = QString::number(result.value, 'g', ExpressionEvaluator::kResultPrecision);
+    m_expression = toEvaluate;
+    m_lastResultText = resultText;
+    m_openParenCount = 0;
+    m_resultShown = true;
+    ui->expressionEdit->setPlainText(m_expression + QStringLiteral(" = ") + resultText);
+    ui->display->setText(resultText);
+}
+
+void CalculatorDesigner::onClear() {
+    m_expression.clear();
+    m_lastResultText.clear();
+    m_openParenCount = 0;
+    m_resultShown = false;
+    m_error = false;
+    ui->expressionEdit->clear();
+    ui->display->setText(QStringLiteral("0"));
+}
+
+void CalculatorDesigner::onBackspace() {
+    if (m_error) { onClear(); return; }
+    if (m_resultShown) return;  // 结果已展示，需先清空或继续输入新表达式
+    if (m_expression.isEmpty()) return;
+
+    const QChar removed = m_expression.at(m_expression.size() - 1);
+    m_expression.chop(1);
+    if (removed == QLatin1Char('(')) --m_openParenCount;
+    else if (removed == QLatin1Char(')')) ++m_openParenCount;
+    refreshDisplays();
+}
+
+QString CalculatorDesigner::displayText() const { return ui->display->text(); }
+
+QString CalculatorDesigner::expressionText() const { return ui->expressionEdit->toPlainText(); }
+
+QString CalculatorDesigner::currentOperandToken() const {
+    int start = m_expression.size();
+    while (start > 0 && isDigitOrDotChar(m_expression.at(start - 1))) --start;
+    return m_expression.mid(start);
+}
+
+int CalculatorDesigner::currentOperandDigitCount() const {
+    const QString token = currentOperandToken();
+    int count = 0;
+    for (const QChar ch : token) {
+        if (ch.isDigit()) ++count;
+    }
+    return count;
+}
+
+QString CalculatorDesigner::lastNumberToken() const {
+    int end = m_expression.size();
+    while (end > 0 && !isDigitOrDotChar(m_expression.at(end - 1))) --end;  // 跳过末尾的运算符/括号
+    int start = end;
+    while (start > 0 && isDigitOrDotChar(m_expression.at(start - 1))) --start;
+    return m_expression.mid(start, end - start);
+}
+
+void CalculatorDesigner::refreshDisplays() {
+    ui->expressionEdit->setPlainText(m_expression);
+    const QString token = lastNumberToken();
+    ui->display->setText(token.isEmpty() ? QStringLiteral("0") : token);
+}
+
+void CalculatorDesigner::showError() {
+    ui->display->setText(QStringLiteral("Error"));
+    m_error = true;
+}